#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n,i,c=0,k=0;
    
    cin >> n;
    int a[n],b[n];
    for(int a0 = 0; a0 < n; a0++){
        cin >> a[a0] >> b[a0];
    }
    for(i=0;i<n-1;i++)
        {
        if(a[i]==a[i+1])
   c++;
        if(b[i]==b[i+1])
k++;
    }
    if(c==n-1 || k==n-1)
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}